Alkyl oligoglucosides are important detergent surfactants since, being nonionic compounds, they are compatible with a large number of other ingredients, but exhibit foaming and cleaning ability which is much more akin to that of anionic surfactants. They are prepared starting from glucose and fatty alcohol, which are acetalized in the presence of acidic catalysts. To shift the reaction equilibrium, the fatty alcohol is generally used in considerable excess, which means that the resulting glucosides then have to be freed from unreacted alcohol at great technical expense, otherwise they then reach the commercial sector in the form of aqueous pastes. However, for the production of solid detergents, primarily of extrudates, heavy powders and more recently also for tablets, alkyl oligoglucosides are increasingly desired in solid supply forms.
The subject-matter of the international patent application WO 97/03165 (Henkel) is a method in which aqueous alkyl oligoglucoside pastes are dried in a fluidized bed. WO 97/10324 (Henkel) discloses a similar method in which the drying and simultaneous granulation is undertaken in a VRV dryer. The prior art thus starts from aqueous pastes, i.e. the relevant methods start from a point at which considerable expenditure has already been made to separate off the unreacted fatty alcohol; accordingly, the products in the production are very expensive.
The object of the present invention was accordingly to provide a method for the production of anhydrous detergent granules with a high content of alk(en)yl oligoglycosides which is free from the described disadvantages, i.e. links in at the earliest possible point in the production of the glycosides and thus minimizes the technical expenditure and the production costs for the granules.